Improvement in safety-valve spring-balances



RAY & CLEVELAND.

Safety Valve Spring Balance.

Patented Dec. 5, 1865.

N. PUERS. Phcla-Llthographnr. \lashmgkm. D. C.

UNITED STATES PATENT OFFICE.

THOMAS S. RAY AND SAMUEL E. CLEVELAND, OF BUFFALO, NEW YORK.

IMPROVEMENT IN SAFETY-VALVE SPRING-BALANCES.

Specification forming part of Letters Patent No. 5] ,350, dated December5, 1865.

To all whom it may concern:

Be it known that we, THOMAS S. RAY and SAMUEL E. CLEVELAND, of the cityofBuft'alo, county of Erie, and State of New York, have invented anImproved Spring-Balance for L0- comotive Safety-Valves; and we do herebydeclare that the following is a full, clear, and exact descriptionthereof, reference being had to the accompanying drawings, making apartof this specification, in which- Figure I is a side sectional elevationof our improved balance; Fi II, a front sectional elevation of same, andFig. IIIa front elevation.

The nature of this invention consists in such combination and arrangementof an index hand and plate with spiral balance-sprin gs andscrewrod as will cause arectilinear expansion or 0011- traction of thebalance-springs to move the index-hand and mark their exact tension, or,in other words, show the steam-pressure which will be required to liftthe safety-valve.

Letters of like name and kind refer to like parts in each of thefigures.

A A represent the spiral balance-springs arranged within the metalliccase B and connected to the bottom thereof by a cross-piece,

a, secured by the screw-shank and nut a Each springis made double-thatis, composed of two springs, one within the other, to obtain greaterstrength and elasticity in a given length. At their upper ends thesprings are connected to the screw valve-rod G by m cans of anequalizing cross-piece, O, which is jointed thereto by a bolt, (3. Thescrew-rod 0 projects up through the top of the case, which has a longboss, I), cast thereon to form a long guide-bearing for the rod andpasses through the end of the safety-valve lever D with a screw-nut, E,above.

The case B being secured to the boiler or other stationary part of thelocomotive, and the safety-valve lever being by construction fixed asagainst a downward movement, the screw ing down of the nut E thereonwill extend the springs A and cause them to hold down on the valve-leverwith a power proportioned to the amount of their extension.

To indicate at once to the glance of the engineer this power which thesprings exert to hold down the safety-valve lever an index hand andplate is combined therewith, as follows:

F represents the indexhand, which is supported on the end of a spindle,G, located between the springs and at the center ofthe case, and havingits bearings in a frame, G, secured to the back of the case. Thisspindle carries a drum, h, to which a chain, h, is connected by one endand wound thereon, said chain being connected at the other end to thescrew-rod O or cross-piece 0, either directly or by an arm, 7L2, so thatan extension movement ot'the screwrod and springs causes the chain tounwind therefrom and revolve the spindle, and with it the index-hand,the hand being brought back when the spring contracts by a light volutespring, N, which is wound up on the spindle as the chain unwindstherefrom.

By this arrangement and connection of the index-hand with the spring anydegree of tension which may be imparted to them by the screwing down ofthe nut E on the screw-rod C will be shown by the index-hand pointing toa number on the graduated and marked indexplate I, said numberrepresenting the force in pounds per square inch which would require tobe applied to the safety-valve to produce the same tension in thesprings. For instance, it the springs be extended by the turning of thenut until the consequent movement of the index-hand shall bring it tothe Fig. 10 on the index-plate, it will show that apressure of tenpounds per square inch on the safety-valve will be required to equal thetension of the sprin If the pressure of steam should be increased beyondthis point the tension of the springs would be insufficient to hold downthe safetyvalve, the lifting of which allows the steam to blow off untilits pressure is again reduced be low the tension of the spring.

It may be found convenient and necessary in some instances to use threeor four springs, A, either double or single. In this case they may allbe connected with the cross-pieces a and Gin same manner as alreadydescribed. The cross piece (1 being hinged to screw rod 0 eqnalizes thepull of the several springs thereon and prevents them from binding it inits bearings b.

YVhere more than one balance-spring is used it will be found necessaryto use this equalizing cross-piece C or to hinge the lower crosspiece ato the case in a similar manner, which would have the same effect.

After continued use the balance-sprin gs may loose some of theirelasticity, so that when unstrained they will fail to regain theirminimum length and bring the index -hand back to its primary position atO, and also permit a mo vement of the indexhand to take place without acorresponding variation in the tension of the springs. This slack orlost movement may be taken up by turning the nut a on the screwshank ofthe lower cross-piece, a, which will have the desired effect withoutaffecting the index-hand.

The index-hand may be revolved by a rack and pinion instead of chain anddrum, if preferred, the rack being attached to the crosspiece 0 and thepinion to the spindle G, or it may be eft'ected by a segment and pinion.

This spring balance is easy of adjustment, and can be set so as topermit the escape or blowing off of the steam at any desired pressure,the index-hand always showing this pressure to the engineer at a glance.

The use of a number of balance-springs com bincs the greatest strengthwith the greatest elasticity, and the whole construction of the balancerenders it durable and not likely to wear and get out of order by thecoustantjars and strains to which locomotive-balances are necessarilysubjected.

Having thus described our invention, what we claim, and desire to secureby Letters Patent, is-

1. The combination and arrangement of an index-hand, F, and plate I withspiral balancesprings A, screw-rod O, and screw-nut E, for the purposeof indicating the pressure of steam required to raise the safety-alve,substantially as described.

2. The combination,with the balance-springs Aand screwrod O, of anequalizing cross-piece C, for the purpose substantially as described.

3. The arrangement of the lower cross-piece with a screwshank and nut,so that any lost movement occasioned by loss of elasticity in thebalance-springs may be taken up without affecting the index-hand,substantially as set forth.

THOS. S. RAY. SAMUEL E. CLEVELAND.

Witnesses W. H. FonBUsH, B. H. MUEHLE.

